Office.com sign-in fails with AADSTS900023 invalid tenant identifier
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MellowCedar42
Is anyone else seeing this sign-in error when selecting "View account" from Office.com? The page reports: "AADSTS900023: Specified tenant identifier '{{{tenantid}}}' is neither a valid DNS name, nor a valid external domain." It has been happening for users in multiple regions, so I'm wondering whether this is a Microsoft service issue or if there's a local workaround or troubleshooting step worth trying.
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Several people are seeing the same error, including users in both Europe and the United States. Since it’s affecting multiple organizations and regions at once, it most likely points to a Microsoft-side authentication problem rather than a tenant configuration issue.
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There doesn’t seem to be a reliable workaround reported yet. Opening a support case with Microsoft and checking the Microsoft 365 service health dashboard are the main practical steps while waiting for the service to recover.
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MellowCedar42: That matches what I’m seeing—this has continued for more than an hour, and the issue isn’t limited to one client or location.